What Are the Most Common Logical Fallacies?

Here's the bad news. There are dozens of logical fallacies - some say even over a hundred!

Here's the good news. You don't need to know all of them. You just need to know the ones that show up again and again in everyday life - the ones being used on you right now, whether you know it or not.

These are the ones worth knowing.

The Ad Hominem Attack is probably the most common fallacy of all. Instead of proving you wrong, someone attacks your character. "Don't listen to him, he's an idiot." It's the fallacy of politicians, trolls and anyone who's ever lost an argument and didn't want to admit it.

The Straw Man Argument is its sneaky cousin. Instead of attacking you directly, someone exaggerates or misrepresents what you said and then attacks that instead. "I said I didn't enjoy that film." "So you hate all films, do you?" It's annoying because it's so hard to pin down in the moment.

The Appeal to Emotion is everywhere. Instead of giving you a good reason, someone provokes a strong feeling to get you to act. Fear. Guilt. Outrage. Pity. Every charity advertisement, every political campaign and every sensational news headline is built on this fallacy to some degree. It's not always wrong to appeal to emotion, but it's a fallacy when it replaces reason.The Appeal to Force is its more aggressive cousin. Instead of provoking an emotion, someone uses a threat. "Agree with me or else." It's the fallacy of bullies, dictators and anyone who's ever said "my way or the highway."

The False Dilemma is one of the most powerful and most used fallacies in politics. It pretends there are only two options when there are actually many more. "You're either with us or against us." "You either support this policy or you don't care about the country." The moment someone tells you there are only two choices, start looking for the third.

The Slippery Slope warns that one small step will inevitably lead to catastrophe - ignoring all the steps in between. "If we allow this once, everything will fall apart." It might occasionally be true. But it's almost always used to shut down reasonable ideas before they've been properly examined.

The Straw Man,  False Dilemma and Slippery Slope are the holy trinity of political manipulation. Learn these three and you'll never watch a political debate the same way again.

Circular Reasoning proves a claim by simply repeating it in different words. "This is the truth because it's true." "The law must be obeyed because it's the law." It sounds like an argument. It isn't.

The False Cause assumes that because one thing happened before another, it must have caused it. You wore your lucky socks and your team won. Obviously the socks did it. It's funny when it's socks. It's dangerous when it's medicine, economics or public policy.

Hasty Generalisation draws a broad conclusion from a tiny sample. "I met two rude people from that city. Everyone there must be rude." We all do this. We all know we shouldn't. We all keep doing it anyway.

The Red Herring distracts you from the real issue by introducing something irrelevant. "Yes, he lied to the public - but he donates a lot to charity." The charity might be real. It has nothing to do with the lying.

The You Too Fallacy deflects criticism by pointing at someone else. "How dare you criticise me for that - you do it too!" Even if true, it proves nothing. Two wrongs have never made a right, no matter how many times people have tried.

Moving the Goalpost changes the terms of an argument after they've already been met. You do everything that was asked of you and suddenly the bar has moved. It's the fallacy of bad bosses, impossible standards and people who simply don't want to admit they were wrong.

The Appeal to Authority uses someone's status to make a claim seem more credible than it is. "This celebrity doctor says it works." Status isn't evidence. Expertise in one field doesn't transfer automatically to another. And even genuine experts can be wrong.

The Appeal to Ignorance argues that because something hasn't been disproved, it must be true. "Nobody has proved it doesn't exist, so it must." Absence of evidence is not evidence of presence. This one is behind more conspiracy theories than any other fallacy on this list.

The Appeal to Tradition argues that because something has always been done a certain way, it must be the right way. "We've done it like this for a hundred years." History is full of things that were done for a very long time before someone pointed out they were wrong.

Confirmation Bias is perhaps the most insidious of all because it operates before you're even aware of it. You unconsciously seek out information that confirms what you already believe and ignore everything that challenges it. It's not just a bug - it's a feature of our brains that every advertiser, algorithm and propagandist knows how to exploit.

The Sunk Cost Fallacy keeps you committed to something long after you should have walked away - simply because you've already invested time, money or energy into it. "I've come this far, I can't stop now." Yes you can. The past is gone. The only question is what makes sense from here.

The Gambler's Fallacy believes that past results influence future outcomes in situations that are actually random. "I've flipped heads five times in a row — tails must be coming up next." The coin doesn't know what it did last time. Neither does the roulette wheel. Neither does the market, most of the time.

The Loaded Question smuggles an assumption into a question to force a damaging answer. "Have you stopped being dishonest yet?" Whether you say yes or no, you've just admitted to being dishonest. Journalists, lawyers and politicians use this one constantly.

The Genetic Fallacy dismisses an idea based on where it came from rather than whether it's true. "That story is from a biased source, so it must be wrong." The source might be biased. The story might still be accurate. These are separate questions.

The No True Scotsman refuses to accept any counterexample to a generalisation by simply redefining the group. "No true fan would say that." "No real patriot would disagree." It's a way of making an argument impossible to challenge - which is always a warning sign.

The Anecdotal Fallacy uses a single personal experience as evidence for a general claim. "My grandfather smoked for sixty years and lived to ninety-five - how dangerous can it be?" One story is not data. But one story feels far more real than a statistic, which is exactly why this fallacy is so effective.

These are the 24 fallacies featured in our game Guess the Fallacy? - each one with its own comic:

Knowing the names is the first step. The real skill is spotting them in the wild - in a conversation, in a headline, in an argument someone is making to your face - and knowing exactly what to say in response.

That's what our game "Guess the Fallacy?" is built for. Not to make you a philosopher. To make you someone who can't be fooled.

See our article "Don't Let Your Kids Be Fooled!" for more on some of the most popular fallacies.